Electrical conductor for lighting purposes.



' tion, my present application I UNITED STATES PATENT OFFICE ISAIDOR LADOFF, OF CLEVELAND, OHIO, ASSIGNOB, BY DIRECT AND MESNE ASSIGN- MEN'IS, OF FIFTEEN ONE-HUNDBEDTHS T0 WALTER D. EDMONDS, OI BOONVILLE, N'EW YORK FIFTEEN ONE-HUNDREDTHB TO PHILIP C. BECK, OF NEW'IORK, N. Y.,

AND SEVENTY ONE-HUNDREDTHSTO ANNA M.

nlmorr.

ELECTRICAT; CONDUCTOR FOR LIGHTING PURPOSES.

Specification of Letters Patent.

No Drawing. Original application filed January 4, 1804, Serial No. 187,698. Divided and this application I filed February 10, 1909. Serial No. 477,204.

To all whom 'it may concern:

Be it known that I, ISADOR LAooFF, a citizen of the United States, now residing in the city of Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in Electrical Conductors for Lighting Purposes, of which the following is a specificaeing a division of my former, now pending, application, Serial No. 187,698, filed January 4, 1904.

My invent-ion.relates to the constitution of that part or arts of an electrical conductor which are a apted to produce illumination when the current is turned on, as for instance the pencils of the are light.

My researches have demonstrated that certain substances, including metals and their oxids, possess properties, which impartto the electric light, derived from conduc-.

tors, containing them, exceptional, if not,

hitherto unattained, candle power, besides other desirable qualities such as unprecedented whiteness, i. e. absence of the red lines objectionable for instance in lights derivedfrom the usual carbon conductors; be-

sides which such conductors so containing the aforesaid substances are much more durable than others previously known. Types of the substances to which I refer are titanium, also its oxid rutile, also silicon, also its oxid silica, etc. Such substances have hitherto proved unavailable on an industrial scale at least, for the purposes in hand, largely on account of-their inadequate electrical conductivity, and they may be classified generally for the purposes of this specification as being substances, including metals, which for the purposes of electric lighting possess exceptional electroluminous but inadequately conductive properties. I have discovered that these substances may be employed in electrical conductors, forlighting purposes, with industrial economy, and with the advantages described, provided they are intermingled in such conductors with another substance, as for instance a metal, possessing the requisite conductivity and stamina to, asit were, support them within and by itself in a state akin to, if not actually of mechanical suspension.

' In my pending application, Serial No.

213,065, filed June 18, 1904, being a division of my application, Serial No. 183,528, filed December 2, 1903, I have particularly described the processes devised by me for combining in pencils or electrodes for are lighting the said oxid of titanium, z. e. rutile with iron. 1

In producing pencils for the arc light comprising the oxid of silicon, c. e. sihca, substantially the same processes and methods are employed by me, though the proportions may be considerably varied without losing characteristic advantages attributable to the silica, but my experience leads me to conclude that thebest results may be obtained from not to exceed 90% of silica and say preferably between 15% and 35%. Are light pencils. so constituted are preferably prepared as follows: The oxid of silicon, silica, is first pulverized and with the resulting powder is mixed pulverized metallic oxid as for instance preferably magnetite. To this mixture 'is added, and thoroughly mixed therewith, a sufiicient quantity of any available binding material, as for instance .in the manner, for instance, in which carbon "pencils are now produced for a similar purpose. The resulting pencils are then allowed to dry in the open air under room' temperatures for several hours, it being important, as will be appreciated in this art, to avoid a too rapid drying which tends to distort the shape of the pencils, After this preliminary air drying, the pencils are further dried'in an oven at a temperature of about 200 deg. C. or thereabout, for a period of about 48 hours. After this the pencils are packed carefully in carbon, and subjected for about two days and two nights to a temperature of from 1200 to 1500 deg. C., after which they are cleaned and thus finished ready for use, care being taken, it will be observed, to expose them as aforesaid to a sufficiently high temperature in the presence of carbon (or carbon monoxid, hydrogen, or any other reducing agent which may be employed) and for a sufficient time to insure substantially complet reduction of the metallic oxid added to the silica as aforesai so as to incorporate into and Within the body of the pencil the metallic element of s such metallic oxid in its elemental state.

I do not, however, wish to belimited to the aforesaid particular method of producing my silica-containing pencil, as the samere sults may obviously be obtained by combining the silica with the more conductive element to be associated therewith in any other way, the essential characteristic of my pres ent invention being the preponderance in an arc light pencil of my said novel mixture of silica with a substance, preferably a metal, more conductive than silica.

I am aware that prior to my invention the I suggestion had been offered that desirable my present invention whichconsists in noncarbonaceous 'electrodesicomposed essentially of'silica and metal, the light from which is attributable to the' so-called flaming or luminous'arc proceeding from the cathode, instead of, as in said carbon electrodes, from 'incandescence of carbon in the crater of the anode! l What I claim as new and desire to secure by Letters Patent is the following, viz

1. An are light electrode consisting essentially of silica associated with metal and characterized, as producing aflaming or luminous are. 4

2. An. arc" light electrode consisting essentially of silica associated with iron and characterized as producing a flaming or luminous arc. a

3; An are light electrode containing at least 15 per cent. of silica mixed with metal and characterized as producing a flaming or luminous arc.

4. An are light electrode containing at least115 per cent. of silica mixedwith iron and characterized as producing a flaming or luminous arc. i

ISADOR LADOFF. Witnesses:

A. J. MITCHELL, JOHN R. ORPUTT. 

